/*
** $Id: lobject.c,v 2.22.1.1 2007/12/27 13:02:25 roberto Exp $
** Some generic functions over Lua objects
** See Copyright Notice in lua.h
*/

#include <ctype.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#define lobject_c
#define LUA_CORE

#include "lua.h"

#include "ldo.h"
#include "lmem.h"
#include "lobject.h"
#include "lstate.h"
#include "lstring.h"
#include "lvm.h"



const TValue luaO_nilobject_ = {LUA_TVALUE_NIL};


/*
** converts an integer to a "floating point byte", represented as
** (eeeeexxx), where the real value is (1xxx) * 2^(eeeee - 1) if
** eeeee != 0 and (xxx) otherwise.
*/
int luaO_int2fb(unsigned int x)
{
    int e = 0;  /* expoent */
    while (x >= 16)
    {
        x = (x + 1) >> 1;
        e++;
    }
    if (x < 8) return x;
    else return ((e + 1) << 3) | (cast_int(x) - 8);
}


/* converts back */
int luaO_fb2int(int x)
{
    int e = (x >> 3) & 31;
    if (e == 0) return x;
    else return ((x & 7) + 8) << (e - 1);
}


int luaO_log2(unsigned int x)
{
    static const lu_byte log_2[256] =
    {
        0, 1, 2, 2, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5,
        6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6,
        7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
        7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
        8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
        8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
        8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
        8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8
    };
    int l = -1;
    while (x >= 256)
    {
        l += 8;
        x >>= 8;
    }
    return l + log_2[x];

}


int luaO_rawequalObj(const TValue *t1, const TValue *t2)
{
    if (ttype(t1) != ttype(t2)) return 0;
    else switch (ttype(t1))
        {
        case LUA_TNIL:
            return 1;
        case LUA_TNUMBER:
            return luai_numeq(nvalue(t1), nvalue(t2));
        case LUA_TBOOLEAN:
            return bvalue(t1) == bvalue(t2);  /* boolean true must be 1 !! */
        case LUA_TLIGHTUSERDATA:
        case LUA_TROTABLE:
        case LUA_TLIGHTFUNCTION:
            return pvalue(t1) == pvalue(t2);
        default:
            lua_assert(iscollectable(t1));
            return gcvalue(t1) == gcvalue(t2);
        }
}


int luaO_str2d(const char *s, lua_Number *result)
{
    char *endptr;
    *result = lua_str2number(s, &endptr);
    if (endptr == s) return 0;  /* conversion failed */
    if (*endptr == 'x' || *endptr == 'X')  /* maybe an hexadecimal constant? */
        *result = cast_num(strtoul(s, &endptr, 16));
    if (*endptr == '\0') return 1;  /* most common case */
    while (isspace(cast(unsigned char, *endptr))) endptr++;
    if (*endptr != '\0') return 0;  /* invalid trailing characters? */
    return 1;
}



static void pushstr(lua_State *L, const char *str)
{
    setsvalue2s(L, L->top, luaS_new(L, str));
    incr_top(L);
}


/* this function handles only `%d', `%c', %f, %p, and `%s' formats */
const char *luaO_pushvfstring(lua_State *L, const char *fmt, va_list argp)
{
    int n = 1;
    pushstr(L, "");
    for (;;)
    {
        const char *e = strchr(fmt, '%');
        if (e == NULL) break;
        setsvalue2s(L, L->top, luaS_newlstr(L, fmt, e - fmt));
        incr_top(L);
        switch (*(e + 1))
        {
        case 's':
        {
            const char *s = va_arg(argp, char *);
            if (s == NULL) s = "(null)";
            pushstr(L, s);
            break;
        }
        case 'c':
        {
            char buff[2];
            buff[0] = cast(char, va_arg(argp, int));
            buff[1] = '\0';
            pushstr(L, buff);
            break;
        }
        case 'd':
        {
            setnvalue(L->top, cast_num(va_arg(argp, int)));
            incr_top(L);
            break;
        }
        case 'f':
        {
            setnvalue(L->top, cast_num(va_arg(argp, l_uacNumber)));
            incr_top(L);
            break;
        }
        case 'p':
        {
            char buff[4 * sizeof(void *) + 8]; /* should be enough space for a `%p' */
            sprintf(buff, "%p", va_arg(argp, void *));
            pushstr(L, buff);
            break;
        }
        case '%':
        {
            pushstr(L, "%");
            break;
        }
        default:
        {
            char buff[3];
            buff[0] = '%';
            buff[1] = *(e + 1);
            buff[2] = '\0';
            pushstr(L, buff);
            break;
        }
        }
        n += 2;
        fmt = e + 2;
    }
    pushstr(L, fmt);
    luaV_concat(L, n + 1, cast_int(L->top - L->base) - 1);
    L->top -= n;
    return svalue(L->top - 1);
}


const char *luaO_pushfstring(lua_State *L, const char *fmt, ...)
{
    const char *msg;
    va_list argp;
    va_start(argp, fmt);
    msg = luaO_pushvfstring(L, fmt, argp);
    va_end(argp);
    return msg;
}


void luaO_chunkid(char *out, const char *source, size_t bufflen)
{
    if (*source == '=')
    {
        strncpy(out, source + 1, bufflen); /* remove first char */
        out[bufflen - 1] = '\0'; /* ensures null termination */
    }
    else    /* out = "source", or "...source" */
    {
        if (*source == '@')
        {
            size_t l;
            source++;  /* skip the `@' */
            bufflen -= sizeof(" '...' ");
            l = strlen(source);
            strcpy(out, "");
            if (l > bufflen)
            {
                source += (l - bufflen); /* get last part of file name */
                strcat(out, "...");
            }
            strcat(out, source);
        }
        else    /* out = [string "string"] */
        {
            size_t len = strcspn(source, "\n\r");  /* stop at first newline */
            bufflen -= sizeof(" [string \"...\"] ");
            if (len > bufflen) len = bufflen;
            strcpy(out, "[string \"");
            if (source[len] != '\0')    /* must truncate? */
            {
                strncat(out, source, len);
                strcat(out, "...");
            }
            else
                strcat(out, source);
            strcat(out, "\"]");
        }
    }
}
